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Topic: Yeast Culturing (Read 7369 times)

My last streaks are just a mess so I need to practice just a little more.

I have grown nice yeast up to 100 ml.So the growing side seams to be working.

I used 16ml vials to do first step (10ml). I think bigger vial would be better.

For 100 ml I used Mason Jars.I was growing two strains. For one strain I had 250 ml jar and for the other I had 500 ml jar.I think I like 500 ml better for this step.For next step I would probably use 2000ml flask with 800 ml wort.

On streaking technique. I did my first plates last week. I used a technique involving 2 plates. Streak one in thirds turning the plate approx. 60° each time. Then without flaming the loop restreak a second plate the same way. I got excellent results for my first time. I realize it is a bit of a "waste" of a plate but it gave me many good single colonies on the second plates despite the fact that I believe I had too much yeast on the loop to begin with.

Only thing I now wonder about is this. Do you need to harvest the colonies before they grow too large? Meaning, should you use the plate as soon as colonies are evident? Mine went about 5 days at room temp before I streaked them on slants and into distilled water, and the colonies were quite thick and wide. Maybe ~1 mm?

Only thing I now wonder about is this. Do you need to harvest the colonies before they grow too large? Meaning, should you use the plate as soon as colonies are evident? Mine went about 5 days at room temp before I streaked them on slants and into distilled water, and the colonies were quite thick and wide. Maybe ~1 mm?

Depending on the depth of the agar, the colonies don’t grow much larger than what you see in the pick I posted. At that point you can pick them.

What I like about the technique where you flame the loop between streaks is that it can handle a very large range for the number of viable colonies on the loop. If you happen to have a lot it may take until the 4th section that you get good isolation. Wile you may have good isolation already in the 1st section if there only a few live ones on your loop.

Its not really necessary to step up from a single colony. Streaking for isolation is helpful for making sure the culture is pure. If you can see that your culture is pure, take a couple loops full and put it in your starter wort. I don't see any benefit is growing from a single cfu.

Edit: I see that you're culturing on slants---:) In this case just barely touch the colony. You really don't need much. The colonies don't have to be large to use them, but give them a reasonable amount of time to grow (2 days or so at room temp)

Its not really necessary to step up from a single colony. Streaking for isolation is helpful for making sure the culture is pure. If you can see that your culture is pure, take a couple loops full and put it in your starter wort. I don't see any benefit is growing from a single cfu.

Edit: I see that you're culturing on slants---:) In this case just barely touch the colony. You really don't need much. The colonies don't have to be large to use them, but give them a reasonable amount of time to grow (2 days or so at room temp)

Oops.

I picked up the whole colony (maybe 2?) for the slants. Overkill I guess. I suppose they will get quite populated eh?

Should I make new slants once these grow?

In this case I did want to isolate as the two yeasts I was culturing had been obtained from bottled beer. A bottle of Ommegang Abbey and a bottle of Victory Helios. They appear (without a microscope) to be nice and healthy.